Annihilation meets Day of the Triffids in this full-on body horror/alien invasion apocalypse.

This is just a story. It can’t hurt you anymore.

Since she was three years old, Anastasia Miller has been telling anyone who would listen that she’s an alien disguised as a human being, and that the armada that left her on Earth is coming for her. Since she was three years old, no one has been willing to listen.

Now, with an alien signal from the stars being broadcast around the world, humanity is finally starting to realize that it’s already been warned, and it may be too late. The invasion is coming, Stasia’s biological family is on the way to bring her home, and very few family reunions are willing to cross the gulf of space for just one misplaced child.

What happens when you know what’s coming, and just refuse to listen?

Mira Grant is the horror pen name for prolific author Seanan McGuire… and basically, I’ll read pretty much whatever she writes, under whichever name. With Mira Grant books, you can count on a certain ickiness (I mean, one of her series has to do with tapeworms!), but always with a strong foundation in character development and relationships.

Here, in Overgrowth, the aliens are coming… although many of their children are already here. Set about five years from now, we follow unfolding events through the eyes of main character Stasia (Anastasia) Miller, a customer service rep and self-described misanthrope who has fewer than a handful of friends, a boyfriend she loves very much, and a cat named Seymour.

Also, since the age of three, Stasia has been telling anyone who’s asked (and even those who haven’t) that she’s an alien, and that her people will be coming to bring her home. You can imagine the flurry of notes from teachers, progressing over time from praise for her precocious imagination to concern about how her insistence on these bizarre fantasies is leading to ostracism by her classmates.

Despite years of therapy as a child, and several managers telling me the joke has gotten old and I’d have an easier time getting promoted if I’d knock it off, I’ve never been able to swallow the urge to tell everyone I spend any extended period of time with that hey, by the way, I’m here because the invasion is coning, and people should probably know. It’s like a nervous tic. Hi, nice to meet you, my name’s Anastasia, I’m secretly an intelligent alien plant and one day everything you love will be devoured.

But as we readers know from the start, it’s not fantasy or imagination. At the age of three, little Anastasia wandered into the woods behind her home, and never came back. Instead, she was consumed and then replaced by an alien plant. The child who came out of the woods was not the child who went into them. But no one has ever actually believed her when she’s insisted on what she is.

We were the changelings of the science fiction age, and that made us both terrifying and untrue.

As the story unfolds, an astronomer releases a recording of a signal that’s definitely alien, causing a massive uproar and worldwide panic. Stasia and her boyfriend Graham decide to go investigate, because there’s something in that signal that seems to be triggering a change in Stasia. Events are set in motion that connect Stasia to others like her. As the invasion gets closer, the alien-humans start to physically change, and they’re targeted by secretive government agents for research and imprisonment. Meanwhile, Stasia has started being able to communicate with her people through a quasi-dream state, and realizes that hard choices are coming. Who does she side with? To whom does her loyalty belong? Can she be blamed for something that she had no control over? And if her friends stick with her, does that make them traitors to their own species?

Overgrowth is complex and multi-faceted, and there’s so much more going on than I can possibly describe. It’s a long book, and requires focus — but it’s absolutely worth the effort. I could not put it down, and could barely come up for air.

There are elements that puzzled me throughout, but the author sticks the landing and ties all the hints and loose plot point together by the end in a way that answers all of my nagging questions. The action is consistently well thought out, the characters are fascinating, and the story arc builds in ways that are unexpected, even as we know that the invasion is inevitable.

The author makes some interesting points about identity and acceptance. Stasia’s boyfriend is a trans man. Even having met him before he transitioned, Stasia immediately accepted his identity.

This could be the moment when I lost him. Because I had always believed him when he told me he was a man, and we had always pretended his belief in me was the same thing, but it wasn’t, was it? It wasn’t the same thing at all. Gender was a social construct and a part of the soul, and humans had always been capable of getting it wrong. I, though…

I was something alien and new, and while we had built a relationship on believing each other, our secrets weren’t the same at all.

Only Graham was still looking at me the way he always had, with love and sincere concern, like he believed I was a human being and deserved to be treasured like one. Or… maybe he’d never believed I was a human being. Maybe I’d been lucky enough to fall in love with one of the only people in the world who understood what it was to tell the truth about your identity, over and over again, until you found the few people who could believe in you.

Stasia’s transformation from weird human who says she’s an alien into a person who realizes that her truth has been more true than she ever knew is startling and evocative and powerful. As she becomes more and more “other”, she has to deal with a changing biology as well as complicated thoughts and feelings about family and survival.

This book is hard to slot neatly into a specific genre. The blurb refers to it as “body horror”, which doesn’t feel entirely accurate to me. I think of body horror as being much more extreme — mutilation, grotesque changes, lots of gore. Here, yes, Stasia’s body changes, but it’s more interesting than gross. There are violent moments with bloody/gory results, but overall, I’d categorize this book as much more heavily science fiction than horror.

However you might describe or shelve it, Overgrowth is fascinating. Stasia is an amazing main character, and I loved seeing her journey. The alien invasion is strange and different and scary, and the plotlines are tightly built and well described. This is a terrific read, and I recommend it highly for anyone who doesn’t mind the idea of creepy plants taking over the world.

Invasion of the Body Snatchers + Little Shop of Horrors. What could go wrong?